Hello,

So I recently put an Access Port on, and I am getting between 2 and 3 on my knock sum. I've heard that anything 3 and under is fine, and that over that you need to do something. So I have a couple quick questions.

1. What do you have to do, if you start getting over 4 on knock sum?
2. What exactly causes knocks?


Thank you for your time!

 

If you are planning on messing with your tune, do a lot of research on what tables are used for and how the values affect the way the engine runs. I know that's a ****ty answer, but how you can best solve your problem depends on factors specific to your car and its environment, so it's hard to say "pull some timing" or "check your fueling" without any more information.

What map are you using, and does it match up to your mods? If it's an OTS map that is compatible, send COBB a log and they'll check it out.

A knock sensor is basically a microphone that listens to the block for bangs. The ECU reads this to decide if the bang happens at the right time or not. If the bang was not at the right time, knock sum is incremented.

What causes knock is usually predetonation, that is, the combustion happens before it is supposed to. What cars usually do when they detect sufficient knock is to retard timing to compensate.

"Phantom knock" is when some other noise is picked up by the knock sensor, it can happen when, say, an exhaust rubs somewhere and the vibration is interpreted by the knock sensor as knock. Usually phantom knock can be diagnosed by checking the knock sensor voltage.

 

Hey, thanks for the reply!!

So im just using the 91 octane stage 1 map, as my car is completely stock.

I will be doing upgrades and getting it pro tuned later, i just wanted to know what the knocks were being caused by.

Me and my buddy installed it last night, and tested it out. Was good, 0-2 knocks. On the way to work today I hit 3 knocks though and i heard that is borderline not good.

So its a timing issue with my detonation?

Perhaps ill log on the way home and send it to cobb to have a look.

Or am i being too dramatic?

On a side note, ive heard of people running stage 2 OTS maps with stock evos. Is this just harder on the car? Still quite new to all this stuff.

Thank you!

 

If you're really worried, I'd say gather a log and send it off. COBB is pretty great about answering questions. They may even respond here.

Stage 2 maps are for cars with mods installed. I would not run an OTS map (or any map for that matter) if it wasn't created with the same mods I was running.

Also, if you're really interested, you can put the stock map back on the car and just run monitors against that. I would bet that you'll see more knock with the stock map than you see with Stage 1, but if you see less, it's definitely something to let the folks at COBB know.

Good luck with your ride!

 

Thanks

So just drove it home and I accelerated fast a few times and I only received 1 max on the knocks. So I think I am good to go. Thanks again

 

I've found that on a fresh re-flash my evo is sensitive to the brand of gas I use. Find a good brand up there and stick to it when you can.

Have you noticed any quirks from the OTS map?

 

I found a good brand, and going to stick with them the best i can. Currently running the 91 octane stage 1 OTS map and i havent noticed any issues. It has only been 1 day though.

 

I'm running the stage 1 for the AMS intake. The stage 1 OTS is night and day from the factory tune, enjoy!